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Migration of Mg and other interstitial metal dopants in GaN (Phys. Status Solidi RRL 7/2017)
Author(s) -
Miceli Giacomo,
Pasquarello Alfredo
Publication year - 2017
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201770337
Subject(s) - dopant , wurtzite crystal structure , diffusion , materials science , ionic radius , condensed matter physics , perpendicular , ionic bonding , gallium , radius , anisotropy , ion , chemistry , doping , zinc , physics , optoelectronics , optics , metallurgy , thermodynamics , geometry , organic chemistry , mathematics , computer security , computer science
Magnesium substitutional to gallium has been hitherto recognized as the only effective p‐type dopant in GaN for envisaging a broader use of this material in electronic devices. Recently, the magnesium interstitial has been shown to play a key role in this process, calling for a deeper understanding of its diffusion properties. Here (article no. 1700081 by Miceli and Pasquarello), the minimum energy paths for the migration of interstitial Mg in wurtzite GaN are studied through density functional calculations. The study also comprises Li, Na, and Be dopants. Three nonequivalent diffusion channels are identified: one parallel and two perpendicular to the c‐axis. Li, Mg, and to some extent Na, diffuse almost isotropically in GaN, with average diffusion barriers of 1.1, 2.1, and 2.5 eV, respectively. Instead Be shows a marked anisotropy with energy barriers of 0.76 and 1.88 eV for diffusion paths perpendicular and parallel to the c‐axis. The diffusion barrier generally increases with ionic charge and ionic radius. The calculated migration barrier for Mg is consistent with the values estimated in a recent channeling experiment.